Big Blue Build Thread

[VANquisher]

Hey All,

As you may have seen in another thread, I finally found my van!

2003 E350 7.3L

While I don't intend to do any rock crawling with the rig, I do plan on mobbing through snow, dirt roads, fire trails, and just generally being bad ***. To accomplish these goals, I've set my eyes on a 4" lift and 4x4 conversion from UJOR!

To that end, I started shopping around for a front axle, and that is when question number one arose.

What is my gear ratio? So far, the only indication I have found is the new vehicle sales receipt that lists a 3.55 ratio Regular Axle as an option. Since this is from 8 years ago, I want to double check. Is the best way to do this by jacking up the car and spinning the wheels?

If it does turn out that my rear end is 3.55 where does that leave me? The axles the UJOR kit is designed for all seem to be 3.73 or 4.10.

Is it possible to change the gear ratio on the axle, or does the entire axle need to be swapped?

If I am going to have to swap the entire axle, should I go for 4.10?

Does changing gear ratios at the axle affect the transmission?

Sorry if these are dumb questions. I'm really new to all this and trying to get my bearings.

 

[loren85022]

Thats a sweet van. Nice color. Chris' magic underneath is really going to make it stand out. It'll sure be *****'n. :sombrero:

 

[nely]

A rear axle swap isnt needed. But youll need adapters for the new 8 lug bolt pattern thats on the 99& up axles. Or get a set of axles then youll have 4 wheel disc, no need for adapters and matching ratios.

I would call a ford dealership. If you give them the last 8 or all of your vin, they can tell you what axle and what ratio you have.

Others are more knowledgeable than i on ratios, but i think 3.73 and 31s are ok to run. Its only 35s and up where gear changes are helpful. I ran a 265/75/16 which is about a 31 without problems with a 3.55 ratio.

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[Clark]

I think I might have everything you need. My engine on my 2000 E350 with the 7.3l blew and I have all of the 4x4 parts you'd need.

Dana 60 Front Axle with 4:10 gears (completely rebuilt 50K ago) with Warn Locking Hubs

Dana 60 Full Float Rear Axle (completely rebuilt 50K ago) with 4:10 gears

Both Drive Shafts correctly sized.

Ujoint Offroad 4x4 van conversion with 4" lift including steering components and F350 Shock mounts.

(5) 33" Treadwright Tires on 17" black steel rims with less that 500 miles on the tires

Heavy Duty Steel Rear Wheel 2" spacers

Centrimatic wheel balancers

Ford 4R100 Reman Transmission with 40K on it (already has 4x4 output shaft)

BW1356 Transfer Case Slight Leak from Front Pinion (you might prefer the nv271 but I had problems with mine so I needed to use the BW1356)

Shortened Fuel Tank

Runnel Heavy Duty Rear Bumper

Fender Flares

Expendable Tow Mirrors

PM me if you're interested in talking

 

[the boogie van]

with a diesel you generally get away with lower engine speeds and higher engine loads, so 3.55 gears aren't a bad thing at all. my 460 EFI has 3.55 gears with 285/75R16s and it works very well overall. it makes power very similar to a diesel.

its a catch-22. lower gears (4.10) would probably get me a little better acceleration up hills and off the line at the expense of higher engine speeds on the freeway (and decreased mileage). ultimately i will probably find 3.73 so towing my trail rig is easier on the drivetrain.

i would decide what size tire you want to run (or the biggest you will likely go, then factor in that you will end up with the next size up:sombrero, then go from there. you can re-gear virtually any axle to whatever common ratio you want. 3.55, 3.73, 4.10, 4.30 (available for some Dana axles) 4.56, etc.

but really, you should just buy the guy above me's van and put your motor in it. thats far less work than what you've got ahead of you...

 

[Loopie]

Nice van!

 

[nely]

An engine swap in a van is harder than a 4x swap. Clarks van is good to buy cuz it has all the ujoint parts on it. Just buy the hanger kit from chris and everything else youd need is on the parts van.

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[Clark]

I agree with Nely. Getting the engine out of the van is not a very fun job, and I would rather switch everything (plus the inside is rather ghetto (great for a surf van, but its below most peoples standards ;-) )). The Ujoint kit is really pretty easy to install. He wouldn't need to buy the hangers since they are already on the van.

 

[nely]

In my opinion the hangers would be hard to line up the old holes with drilling new holes on new vans frame. Especially since the inner rear holes line up with radiator and core support. You can measure i guess bit i feel its easier to just buy hangers and drill them to your own van. Plus he will need the sleeve thats welded to frame for shackle.

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[MadChad]

After talking to the guys at work who have 7.3 diesel F350's, for the purpose of getting better gas mileage they have switched to 3.55 and say they can still tow 5,000 pounds. I've been thinking about this option myself.
We just returned from a 1,200 mile trip and the van with 4.10 on it averaged 16 mpg, now I'm planning to take meny more long range trips so mileage will be important and also a tunner will help.
Good luck on your build, Chad.

 

[1sweetvan]

After talking to the guys at work who have 7.3 diesel F350's, for the purpose of getting better gas mileage they have switched to 3.55 and say they can still tow 5,000 pounds. I've been thinking about this option myself.
We just returned from a 1,200 mile trip and the van with 4.10 on it averaged 16 mpg, now I'm planning to take meny more long range trips so mileage will be important and also a tunner will help.
Good luck on your build, Chad.

How fast did you drive and how loaded were you to get 16 MPG?

 

[nely]

Mileage will vary. I got 20 going 65 with 3.55 265/75 tires on my eb van with 4" lift on the front. Prerunner status. And a dp tuner set to 60hp "economy" mode. The tuner didnt seem to help my mileage but the fun factor defenitly went up. The diesels can put out some power with just a proper tune.

4.10 seem low in a van if your looking for mileage. 4.70 are what i found to be a good ratio "in theroy" for 37s, since i havent done a gear change yet. But on paper the rpms match and should work good for me.

3.55 or 3.73 should be a good match to a 31 or 265/75 tire. 4.10s are good if your wanting low end torque or compensating for low power and big tires like on a 4x toyota. The diesel has enuff of both.

Clark has a 4x and 4.10 on his van. Maybe he can chime in on his mileage in a vehicle we all want to build.


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[1sweetvan]

Thanks.

I really would like to hear from Chad however. How about it Chad? How fast were you driving and how loaded up were you to get 16 on a road trip? I'm really just curious. 1200 miles is a good distance to measure MPG.

 

[Clark]

I was much happier with the 4:10s than I was with the 3.:73s. The main thing I noticed that effected my mileage was how heavy my foot was. I had single shot injectors for the last 12k I owned the van. In theory you get better mileage with single shots, but I think I choose to utilize the performance gains instead :wings:

 

[MadChad]

Average was around 70mph, load was light. Speed(rpm) also plays in the equation. Also the van is still 2 wheel drive on stock wheels and since its all stock it has to have the two shot injectors on it.